Arie swordsmanship about copying

We're starting to get more information on the Arie Family in the main story.
Arie Swordsmanship is not just of Arie Family.
Normal people can learn the forms of the technique. They're good with swords for a reason.
It's just that they can't use it as a Arie member can;;

[Blogpost translation] Season 2 Episode 217